В всех квадратиках самое первое пример, нужно продолжить

1) i will ride my bike tomorrow 2) my grandma got two letters yesterday 3)they were in the country last summer

1. the boys are playing football now. they are tired. they have been playing football an hour and a half.

2) tom began talking on the phone an hour ago. i think he should finish. he has been talking on the phone for more than an hour already.

3) roy came to see  the dentist at nine o`clock. it is 9: 30 now.

roy has been waiting for the doctor since 9: 00 a.m.

4) colin became a professor in 1998. he has been working at the university since he became a professor.

5) the greens went to canada last summer. they are living in canada now. they have been living in canada for about a year.

1)when he will write a letter?

2)where hobbit will go next year?

3)whenthey will clean the room?

4)

5)what we will play tomorrow?

chemical pollution of atmosphere.the person pollutes atmosphere in the millenia, however consequences of the use of fire which it used all this period, were insignificant. it was necessary to be reconciled by that the smoke disturbed to breath and that soot laid down a black cover on a ceiling and walls of dwelling. received heat for the person was more important, than pure air and incomplete walls of a cave. this initial air pollution did not represent a problem for people lived then small groups, occupying unreasonably extensive untouched environment. and even the considerable concentration of people in rather small territory as it was in a classical antiquity, was not accompanied still by serious consequences.so was up to the beginning of the nineteenth century. only for last hundred years development of the industry "has presented" us with such productions which consequence in the beginning the person could not present itself yet. there were the cities-millionaires which growth it is impossible to stop. all is result of great inventions and gains of the person.the basic polluting substances.basically there are three basic sources of pollution of atmosphere: the industry, household boiler-houses, transport. the share of each of these sources in general, air pollution strongly differs depending on a place. now that most strongly pollutes air industrial production. sources of pollution - thermal power stations which together with a smoke throw out sulphurous and carbonic gas in air; the metallurgical enterprises, especially nonferrous metallurgy which throw out in air оксиды nitrogen, hydrogen sulphide, chlorine, fluorine, ammonia, connections of phosphorus, a particle and connection of mercury and arsenic; chemical and cement works. harmful gases get to air as a result of burning of fuel for needs of the industry, heating of dwellings, work of transport, burning and processing household and industrial wastes.